Project Summary/Abstract Kenya has one of the world's largest HIV and AIDS epidemics, with about 1.6 million people living with HIV and 25,000 people dying from AIDS in 2018. Adolescents, especially girls, are particularly vulnerable to HIV. In western Kenya, over 50% of adolescents had sexual intercourse before the age of 18; however, youth between the ages of 15-19 have low rates of condom use and HIV testing. Stigma negatively affects HIV prevention behaviors, including condom use and HIV testing. In Kenya, complex interactions between social capital, religiosity, and biological sex shape societies' discriminating attitudes towards youth perceived to be infected with HIV (i.e., social stigma), which, in turn, affects HIV prevention. The University of Iowa is partnering with Tangaza University College (Nairobi) and Gynocare Women's and Fistula Hospital (Eldoret) to elucidate the complex relationship between social capital, religiosity, sex, and HIV-related stigma among adolescents (ages 15-19) and its impact on HIV prevention in western Kenya. Focusing on three counties in western Kenya, this two-year, mixed-methods project will develop contextualized measures of social capital, religiosity, and HIV-related stigma (Aim 1); determine the relationship between social capital, religiosity, sex, HIV-related stigma, and HIV-preventive behaviors using quantitative methods (Aim 2); and explicate the relationships between social capital, religiosity, sex, and HIV-related stigma using qualitative methods (Aim 3). For Aim 1, cognitive interviewing techniques will be used with a purposive sample of 12 girls and 12 boys to contextualize and validate a 13-item social capital instrument, a 10-item religiosity scale, and a 27-item instrument to assess social stigma related to HIV. The psychometric properties of these contextualized measures will be assessed through a pilot survey administered to a sample of 100 adolescents. For Aim 2, a survey that includes the validated measures developed in Aim 1 will be administered to 765 randomly selected unmarried girls and boys (ages 15-19) from in western Kenya. Multiple regression analysis will be used to examine the association between (1) social capital and HIV-preventive behaviors (i.e., condom use and HIV testing), and the potential mediating role of social stigma; and (2) social capital and social stigma, and the potential moderating role of religiosity and sex. For Aim 3, 36 in-depth interviews will be conducted with adolescents (ages 15-19), parents, religious leaders, teachers, and health care providers to better understand the complex relationships identified in Aim 2. Led by an experienced Executive Committee and Advisory Board, this study will develop three new scales and identify potential pathways to reduce HIV-related stigma and increase HIV-preventive behaviors among adolescents in western Kenya. This project will also increase the research capacity of two Kenyan institutions to examine HIV-related stigma and its consequences. Ultimately, this partnership will allow us to design effective interventions to address stigma and promote young people's health throughout Kenya.